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Search Publications by: Angela R. Hight Walker (Fed)

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Displaying 126 - 150 of 173

Comparative Measures of Single Wall Carbon Nanotube Dispersion

September 14, 2006
Author(s)
Jeffrey A. Fagan, Brian Landi, Idan Mandelbaum, Vardhan Bajpai, Barry J. Bauer, Kalman D. Migler, Jeffrey R. Simpson, Angela R. Hight Walker, Ryan Raffaelle, Erik K. Hobbie
Model polymer composites of DNA wrapped single-wall carbon nanotubes (SWNTs) dispersed in polyacrylic acid are used for a systematic comparison of the different metrologies currently used to evaluate SWNT dispersion. Application of a pH-controlled

Method for Measuring the Raman Gain Tensor in Optical Fiber

April 7, 2006
Author(s)
Idan Mandelbaum, M Bolshtyansky, T F. Heinz, Angela R. Hight Walker
In this paper we introduce a technique to measure the tensor properties of the Raman gain in a short piece (10m) of silica based polarization maintaining optical fiber. We present the results of the measurement and show agreement with new and previous bulk

Quantitative, Interactive Measurement of Tissue Engineering Scaffold Structure Using Immersive Visualization

January 1, 2006
Author(s)
Jeffrey Fagan, Erik K. Hobbie, Brian Landi, Idan Mandelbaum, Vardhan Bajpai, Barry J. Bauer, Kalman D. Migler, Jeffrey R. Simpson, Angela R. Hight Walker, Ryan Raffaelle
At NIST, we are using new approaches to better understand and quantify the structure of tissue engineering scaffolds. This approach uses immersive visualization (IV) and is inherently three dimensional, multivariate and interactive, providing real-time

Rotational Spectra, Conformational Structures and Dipole Moments of Thiodiglycol by Jet-Cooled FTMW and Ab Initio Calculations

May 1, 2004
Author(s)
L H. Xu, Q Liu, R D. Suenram, Francis J. Lovas, Angela R. Hight Walker, J O. Jensen, A C. Samuels
The rotational spectra of three low-energy conformers of thiodiglycol (TDG) (HOCH2CH2SCH2CH2OH) have been measured in a molecular beam using a pulsed-nozzle Fourier-transform microwave spectrometer. To determine the likely conformational structures with ab

Rotational Spectra of the Diastereomers of Soman

April 1, 2004
Author(s)
R D. Suenram, R S. DaBell, Angela R. Hight Walker, D J. Lavrich, David F. Plusquellic, M W. Ellzy, J M. Lochner, L Cash, J O. Jensen, A C. Samuels
The pure rotational spectrum of the nerve agent Soman has been recorded and assigned using a pulsed molecular beam Fourier transform microwave spectrometer. The spectrum consists of transitions from two different isomers that are likely the [SS] (or [RR])

Continuous-Wave Terahertz Spectroscopy of Plasmas and Biomolecules

March 1, 2004
Author(s)
David F. Plusquellic, T M. Korter, Gerald T. Fraser, R J. Lavrich, Eric C. Benck, C R. Bucher, Angela R. Hight Walker, J L. Domenech
Continuous-wave linear-absorption spectroscopy based on THz radiation generated by solid-state photomixers has been applied to the investigation of the dynamics of biomolecules in polyethylene matrices and to line shape studies of HF for diagnostics of

Surface Enhanced Raman Spectroscopy in a Microfluidic Device

February 1, 2004
Author(s)
D Dunmire, D B. Romero, Guangjun Cheng, Angela R. Hight Walker
Surface enhanced Raman spectroscopy (SERS) is employed to study the solution phase vibrational structure of molecules on gold and silver colloids. Gold and silver colloids show large enhancement factors enabling sub-micromolar detection limits. Using a

Synthesis of Bioconjugated Magnetic Nanoparticles for Magneto-Raman Study

February 1, 2004
Author(s)
Guangjun Cheng, D B. Romero, D Dunmire, Angela R. Hight Walker
We are investigating the effects of an externally applied magnetic field on the structure and magnetic properties of biomolecules (DNA and proteins). A newly constructed, magneto-Raman confocal microscope system couples a cryo-magnet to a triple grating

Rotational Spectrum of Soman

January 1, 2004
Author(s)
R S. DaBell, R D. Suenram, Angela R. Hight Walker, R J. Lavrich, David F. Plusquellic, M W. Ellzy, J M. Lochner, L Cash, J O. Jensen, A C. Samuels

Conformational Analysis of the Jet-Cooled Peptide Mimetic Ethylacetamidoacetate from Torsion-Rotation Spectra

September 1, 2003
Author(s)
R J. Lavrich, Angela R. Hight Walker, David F. Plusquellic, I Kleiner, R D. Suenram, Jon T. Hougen, Gerald T. Fraser
Rotational spectra of two conformers of the dipeptide mimetic, ethyl acetamidoacetate, were measured in a molecular beam using a Fourier-transform microwave spectrometer. In each conformer, internal rotation of the acetyl methyl group gives rise to

Experimental Studies of Peptide Bonds: Identification of the C 7 eq Conformation of the Alanine Dipeptide Analog N-Acetyl-Alanine N'-Methylamide From Torsion-Rotation Interactions

January 1, 2003
Author(s)
R J. Lavrich, David F. Plusquellic, R D. Suenram, Gerald T. Fraser, Angela R. Hight Walker, M J. Tubergen
Rotational spectra of the bio-mimetic molecule, alanine dipepitide and the double 15N( 15N 2) isotopomer have been observed using a pulsed-molecular-beam Fourier transform microwave spectrometer. The spectra reveal large tunneling splittings from the

The Validation of Fourier-Transform Microwave Spectroscopy for Trace-Gas Analysis

February 1, 2002
Author(s)
Pamela M. Chu, R D. Suenram, Angela R. Hight Walker, R S. DaBell, George C. Rhoderick, Gerald T. Fraser
There is strong interest by regulatory agencies and automobile manufacturers, motivated in large part by increasingly stringent emission standards, for measurement tools capable of quantifying various hydrocarbons, oxygenated hydrocarbons, etc., in

Spontaneous Coherent Microwave Emission and the Sawtooth Instability in a Compact Storage Ring

May 1, 2001
Author(s)
Uwe Arp, Gerald T. Fraser, Angela R. Hight Walker, Thomas B. Lucatorto, K K. Lehmann, K Harkay, N Sereno, K Kim
Strong evidence for self-excited emission of coherent synchrotron radiation in the microwave spectral region was observed at the Synchrotron Ultraviolet Radiation Facility SURF III electron storage ring at the National Institute of Standards and Technology

Rotational Spectrum of Sarin

January 1, 2001
Author(s)
Angela R. Hight Walker, R D. Suenram, A C. Samuels, J O. Jensen, M W. Ellzy, J M. Lochner, D Zeroka